Conservative Currents of Boundary Charges in Gravity
arXiv:hep-th/9902108
Abstract
The boundary charges which constitute the Virasoro algebra in 2+1 dimensional anti-de Sitter gravity are derived by way of Noether theorem and diffeomorphic invariance. It shows that the boundary charges under discussion recently exhaust all the independent nontrivial charges available. Therefore, the state counting via the Virasoro algebra is complete.
10 pages, Latex, no figures,added reference[2], corrected some typos